Filthy Air Likely to Persist Across the Bay Area Through the Weekend

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A helicopter drops water on a ridge burning due to the Glass Fire, near Old Lawley Toll Road north of Calistoga on Sept. 30, 2020. (Beth LaBerge/KQED)

Dense smoke from the Glass Fire shrouds Napa, Santa Rosa and St. Helena. Air sensors in these communities are registering hazardous levels, which indicates toxic fumes could provoke health problems in anyone, not only people with sensitive respiratory systems.

Filthy plumes pervade much of the Bay Area. Conditions are rapidly declining in San Francisco and the East Bay, and regulators extended a Spare the Air alert through next Tuesday.

“We are expecting air quality impacts well into early next week from the Glass Fire,” said Kristine Roselius, a spokesperson for the Bay Area Air Quality Management District.

Nasty air is expected to saturate the region Thursday and Friday, and Roselius says she doesn’t expect clear skies until firefighters quell the blaze. The Glass Fire is currently 5% contained.

Doctors say a good rule of thumb is to let your nose lead. If the air smells like a campfire, it’s best to relax indoors with the windows closed. You can even tape the edges to prevent smoke leaks.


Air quality experts recommend turning your air conditioner on recirculate and running an air filter, if possible. Portable HEPA air purifiers can be purchased at hardware stores or online. Alternatively, you can construct your own unit out of a box fan, a MERV filter and heavy-duty tape, for about $50. If you must leave the house, an N95 mask with an external valve  is optimal protection for smoke. To protect others from the coronavirus you need to tape the valve closed or wear a cloth mask on top.

Monitor Bay Area air quality here. If you’re prone to refreshing PurpleAir or AirNow throughout the day and the two sites conflict, try a new fire and smoke map that blends both services. The amalgamation provides readings taken from PurpleAir’s low-cost sensors and those from official government monitoring devices; the circles represent official monitors, the squares indicate PurpleAir sensors, and the triangles show temporary monitors set up by federal agencies.

Tiny particles in wildfire smoke can trigger burning eyes, a scratchy throat, bronchitis and even heart attacks. However, Roselius says the health risks sparked by heat are more perilous than smoke. The forecast calls for toasty temperatures in many parts of the Bay Area over the next few days. If you start to overheat, you can open a window to get some air flow, or depart your home and find relief at a public cooling center nearby.